CIM Initial Environment Flake

This flake sets up a development environment along with a Neo4j database service.

Inputs

• nixpkgs: Points to the nixos-unstable branch of the Nix packages collection, which is used to fetch the necessary packages.
• flake-utils: A utility flake from numtide used to simplify flake usage across multiple systems.

Outputs

The outputs function generates configurations based on the system architecture provided. It leverages flake-utils to support multiple systems without repeating code.

Packages and Configuration

For each system, it imports packages from nixpkgs with the following adjustments:

• Allows unfree packages to be installed (config.allowUnfree = true).

Neo4j Service

It configures the Neo4j service to be enabled by adding it to the modules array. This part of the configuration is directly inlined in the flake, illustrating the ability to mix NixOS module configurations directly in flakes.

Development Shell

Defines a devShells.default environment that includes various build and development tools such as just, cacert, openssl, pkg-config, zlib.dev, graphviz, and neo4j itself. This shell is tailored for development, ensuring all necessary tools and libraries are available.

Shell Hook

Upon entering the shell, it checks for a .env file and exports its contents, allowing for environment variable management outside the Nix configuration. This is particularly useful for managing secrets or dynamic configuration that shouldn't be hardcoded in the flake.

Key Takeaways

• The flake is designed for development, with tools and a Neo4j database ready out of the box.
• It showcases the power of Nix flakes in creating reproducible and customizable development environments.
• The configuration makes use of flake-utils to streamline multi-system support and reduce boilerplate.
• Environment variables can be managed through a .env file, enhancing the flexibility of the development environment.